macOS: Allow to customize Hide, Minimize, and Quit global menu shortcuts

All previously hard-coded shortcuts under macOS can be configured now.

kitty/state.h

@@ -320,6 +320,10 @@ typedef enum {
     TOGGLE_MACOS_SECURE_KEYBOARD_ENTRY,
     TOGGLE_FULLSCREEN,
     OPEN_KITTY_WEBSITE,
+    HIDE,
+    HIDE_OTHERS,
+    MINIMIZE,
+    QUIT,
 
     NUM_COCOA_PENDING_ACTIONS
 } CocoaPendingAction;